usefor-article-03 February 2000

7.3.1.  Single group
   The "mvgroup" control message requests that the first specified group
   be moved to the second specified group. The message body MUST contain
   a "application/news-groupinfo" (7.1.2) containing machine- and
   human-readable information about the new group, and possibly other
   subparts as for a newgroup control message.

   When this message is received, the new group SHOULD be created (and
   MUST be moderated if a newgroup-flag "moderated" is present) and all
   existing articles SHOULD be copied or moved to the new group; then
   the old, now empty group SHOULD be removed.

   If the old group does not exist, the message is ignored unless the
   new group does not exist either, in which case the message SHOULD be
   treated as if it had been an equivalent "newgroup" message.

   If both groups exist, the groups MAY be "merged". If this is done, it
   MUST be done correctly, i.e. implementations MUST take care that the
   messages in the group being deleted are renumbered accordingly to
   avoid overwriting articles in one group with those of the other, and
   that crossposted articles do not appear twice. Otherwise, the old
   group is just removed.

        NOTE: Due to the severe difficulties of implementing this
        merging, those proposing to merge existing groups using this
        control message should be aware that it may not be implemented
        on many (if not most) sites, and should therefore be prepared
        for such disruption as may ensue.

   An indication that the old group was replaced by the new group MAY be
   retained by the serving agent so that continuity of service may be
   maintained, and clients made aware of the new arrangements.

        NOTE: Some serving agents that use an "active" file permit an
        entry of the form "oldgroup xxx yyy =newgroup", which enables
        any articles arriving for oldgroup to be diverted to newgroup,
        and could even enable users already subscribed to oldgroup to
        receive articles from newgroup instead.

   In all cases, the information conveyed in the "application/news-
   groupinfo" body part is applied to the new group.

   Until most serving agents conform to this standard, whenever a
   mvgroup control message for a single group is issued, a corresponding
   pair of rmgroup and newgroup control messages SHOULD be issued a few
   days later.